Rib Cage Measurement Reproducibility Using Biplanar Stereoradiographic 3D Reconstructions in Adolescent Idiopathic Scoliosis

Study design: A reproducibility study of preoperative rib cage 3D measurements was conducted for patients with Adolescent Idiopathic Scoliosis (AIS). Objective: to assess the reliability of rib cage 3D reconstructions using biplanar stereoradiography in patients with AIS before surgery. Summary: no prior reliability study has been performed for preoperative 3D reconstructions of the rib cage by using stereoradiography in patients with preoperative AIS. Materials: this series includes 21 patients with Lenke 1 or 2 scoliosis (74°+ - 20). All patients underwent low-dose standing biplanar radiographs. Two operators performed reconstructions twice each. Intraoperator repeatability, interoperator reproducibility and Intraclass coefficients (ICC) were calculated and compared between groups. Results: The average rib cage volume was 4.7l L (SD ± 0.75 L). SDr was 0.19 L with a coefficient of variation of 4.1% ; ICC was 0.968. The thoracic index was 0.6 (SD ± 0.1). SDr was 0.03 with a coefficient of variation of 4.7 % and a ICC of 0.820. As for the Spinal Penetration Index (6.4% ; SD ± 2.4), SDr was 0.9 % with a coefficient of variation of 14.3 % and a ICC of 0.901. The 3D rib hump SDr (average 27° ± 8°) was 1.4°. The coefficient of variation and ICC were respectively 5.1% and 0.991. Conclusion: 3D reconstruction of the rib cage using biplanar stereoradiography is a reliable method to estimate preoperative thoracic parameters in patients with AIS

Biplanar stereoradiography predicts pulmonary function tests in adolescent idiopathic scoliosis: a cross-sectional study

Purpose Various spinal and rib cage parameters measured from complex examinations were found to be correlated with preoperative pulmonary function tests (PFT). The aim was to investigate the relationship between preoperative rib cage parameters and PFT using biplanar stereoradiography in patients with severe adolescent idiopathic scoliosis. Methods Fifty-four patients, 45 girls and nine boys, aged 13.8 ± 1.2 years, with Lenke 1 or 2 thoracic scoliosis (> 50°) requiring surgical correction were prospectively included. All patients underwent preoperative PFT and low-dose biplanar X-rays. The following data were collected: forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC ratio, residual volume, slow vital capacity (SVC), total lung capacity (TLC), rib cage volume (RCV), maximum rib hump, maximum width, mean thoracic index, spinal penetration index, apical vertebral rotation, main curve Cobb angle (MCCA), T4–T12 kyphosis. The primary outcome was the relationship between rib cage parameters and PFT. The secondary outcome was the relationship between rib cage parameters and spine parameters. Data were analyzed using Spearman’s rank test. A multivariable regression analysis was performed to compare PFTs and structural parameters. Significance was set at α = 0.05. Results The mean MCCA was 68.7° ± 16.7°. RCV was highly correlated with all pulmonary capacities: TLC (r = 0.76, p < 0.0001), SVC (r = 0.78, p < 0.0001) and FVC (r = 0.77, p < 0.0001). RCV had a low correlation with FEV1/FVC (r = − 0.34, p = 0.014). SPI was not correlated with any pulmonary parameters. Conclusion Rib cage volume measured by biplanar stereoradiography may represent a prediction tool for PFTs.BiomecAM chai

Sagittal plane assessment of manual concave rod bending for posterior correction in adolescents with idiopathic thoracic scoliosis (Lenke 1 and 3)

Objectives The objectives of this study were to evaluate the repeatability and reproducibility of a method for measuring freehand rod bending and to analyze the relationship between the rod's bend and the resulting sagittal correction. Materials and methods All the children who underwent correction by posterior translation using pedicle screws at all levels were included prospectively in 2018 and 2019. The rod's sagittal parameters were measured retrospectively by three independent surgeons on two separate occasions using the same protocol. After the rods were bent but before they were inserted, the surgeon traced the contours of the rods on a sheet of paper that was later scanned and analyzed semiautomatically. The spinal parameters were calculated based on biplanar radiographs taken preoperatively, postoperatively and at the final follow-up visit. Patients who had less than 10° thoracic kyphosis (T5–T12) made up the “Lenke N−” subgroup. Results Thirty patients were included (14 of whom were Lenke N−) who had a Cobb angle of 59.2 ± 11.3° preoperatively and 13.3 ± 8.4° postoperatively (p 0.9 (excellent). The mean kyphosis of the concave rod was 48.4 ± 5.7° (38.3–60.9°). The mean change in T5–T12 kyphosis was 9.7 ± 10.8° (−14.3–30.8°) (p < 0.0001) in the entire population, while it was 17.7 ± 7.1° (5.5–30.8°) (p < 0.0001) in the Lenke N− subgroup. The change in thoracic kyphosis was positively correlated with the kyphosis of the concave rod (rho = 0.52; p = 0.003). Conclusion This study found excellent reproducibility and repeatability of measuring freehand rod bending. The kyphosis applied to the concave rod is positively correlated to the change in the resulting kyphosis and made it possible to restore satisfactory thoracic kyphosis

A Novel Classification of 3D Rib Cage Deformity in Subjects With Adolescent Idiopathic Scoliosis

Study Design: This was a multicentric cross-sectional descriptive study. Objective: To analyze patterns of 3D rib cage deformity in subjects with adolescent idiopathic scoliosis (AIS) and their relationship with the spinal deformity. Summary of Background Data: Subjects with AIS present with rib cage deformity that can affect respiratory functions. The 3D rib cage deformities in AIS and their relationship to the spinal deformity are still unelucidated. Methods: A total of 200 AIS and 71 controls underwent low-dose biplanar x-rays and had their spine and rib cage reconstructed in 3-dimensional (D). Classic spinopelvic parameters were calculated in 3D and: rib cage gibbosity, thickness, width, volume and volumetric spinal penetration index (VSPI). Subjects with AIS were classified as: group I with mild rib cage deformity (n=88), group II with severe rib cage deformity (n=112) subgrouped into IIa (high gibbosity, n=48), IIb (high VSPI, n=48), and IIc (both high gibbosity and VSPI, n=16). Results: Groups IIa and IIb had a higher Cobb angle (33 vs. 54 degrees and 46 degrees, respectively) and torsion index (11 vs. 14 degrees and 13 degrees, respectively) than group I. Group IIb showed more severe hypokyphosis (IIb=21 degrees; IIa=33 degrees; I=36 degrees; control=42 degrees) with a reduced rib cage volume (IIb=4731 cm3; IIa=4985 cm3; I=5257 cm3; control=5254 cm3) and thickness (IIb=135 mm; IIa=148 mm; I=144 mm; control=144 mm). Group IIa showed an increasingly large local gibbosity descending from proximal to distal levels and did not follow the axial rotation of the spine. Group IIc showed characteristics of both groups IIa and IIb. Conclusions: This new classification of 3D rib cage deformity in AIS shows that the management of cases with high VSPI (groups IIb and IIc) should focus on restoring as much kyphosis as possible to avoid respiratory repercussions. Treatment indications in groups I and IIa would follow the consensual basic principles reported in the literature regarding bracing and surgery

Dose, image quality and spine modeling assessment of biplanar EOS micro-dose radiographs for the follow-up of in-brace adolescent idiopathic scoliosis patients.

Purpose: The aim of this study was to compare the radiation dose, image quality and 3D spine parameter measurements of EOS low-dose and micro-dose protocols for in-brace adolescent idiopathic scoliosis (AIS) patients. Methods: We prospectively included 25 consecutive patients (20 females, 5 males) followed for AIS and undergoing brace treatment. The mean age was 12 years (SD 2 years, range 8-15 years). For each patient, in-brace biplanar EOS radiographs were acquired in a standing position using both the conventional low-dose and micro-dose protocols. Dose area product (DAP) was systematically recorded. Diagnostic image quality was qualitatively assessed by two radiologists for visibility of anatomical structures. The reliability of 3D spine modeling between two operators was quantitatively evaluated for the most clinically relevant 3D radiological parameters using intraclass correlation coefficient (ICC). Results: The mean DAP for the posteroanterior and lateral acquisitions was 300 ± 134 and 433 ± 181 mGy cm2 for the low-dose radiographs, and 41 ± 19 and 81 ± 39 mGy cm2 for micro-dose radiographs. Image quality was lower with the micro-dose protocol. The agreement was "good" to "very good" for all measured clinical parameters when comparing the low-dose and micro-dose protocols (ICC > 0.73). Conclusion: The micro-dose protocol substantially reduced the delivered dose (by a factor of 5-7 compared to the low-dose protocol) in braced children with AIS. Although image quality was reduced, the micro-dose protocol proved to be adapted to radiological follow-up, with adequate image quality and reliable clinical measurements. These slides can be retrieved under Electronic Supplementary Material.No funding was secured for this study

Analysis of the upper airway by the acoustic reflection method in children with mucopolysaccharidosis: Acoustic reflection in mucopolysaccharidosis

International audienceBackground Upper airway obstruction is common in children with mucopolysaccharidosis. The acoustic reflection method is a noninvasive technique that can analyse the calibre of the upper airways. The aim of the study was to evaluate the feasibility of the acoustic reflection method in children with mucopolysaccharidosis, and to compare the characteristics of the upper airways evaluated by the acoustic reflection method in patients with mucopolysaccharidosis to matched healthy counterparts. Methods Open, single centre, prospective, study Results Accurate acoustic reflection measurements could be obtained in 7 of 10 patients (mean age: 10.4 ± 3.9 years; mucopolysaccharidosis type II (n=3); type IV (n=2), type VI (n=1), and fucosidosis (n=1)). The mean minimum cross-sectional area was lower in mucopolysaccharidosis patients (1.6 ± 0.3 cm²) as compared to 14 healthy counterparts (1.8 ± 0.3 cm²; p=0.03). The mean resistance of the airways was significantly higher in the MPS group (7.9 ± 1.8 cmH2O.l-1.s) as compared to the controls (5.5 ± 1.2 cmH2O.l-1.s; p=0.006). Conclusion This study is the first to analyze the upper airways by the noninvasive acoustic reflection method in children with mucopolysaccharidosis. Due to a lack of cooperation, reliable measurements could only be obtained in 70% of a selected group of patients. Children with mucopolysaccharidosis have significant upper airway obstruction as assessed by the reduction of the minimal cross-sectional area of the upper airways and the increase in airway resistance

Protocol for Electrical Conductivity Signal Collection and Processing in Scoliosis Surgery

Introduction. Pedicle screw placement is a common procedure in spinal surgery. The misplacement rate with lateral and medial cortical perforation is 5–11%. Several techniques are used to decrease this rate. Many studies proved that electrical conductivity increases accuracy during pedicle screw placement but no study has interpreted conductivity values. Methods. The data are collected from patients operated for scoliosis in a single university hospital. After the posterior surgical approach is made, each pedicle is prepared classically. Instead of the classic curved pedicle probe, the surgeon uses a probe with the same shape that measures the conductivity at its tip. Conductivity values are recorded through a Bluetooth application. Each pedicle trajectory is then qualified after manual palpation with a feeler. A trajectory is qualified as optimal when palpation shows a bone tunnel without any breach, breached when there was a breach, and a modification of the probe direction was needed. A trajectory that does not meet the abovementioned definitions is excluded from the statistical analysis. Results. 21 patients with 457 pedicles are recorded. The average age of the population is 14.71 ± 1.86 years. 17 patients (81%) have idiopathic adolescent scoliosis. One patient has Rett syndrome, one has hypotonia, one has cerebral palsy, and one has congenital malformation. The depth of the instrument is measured semiautomatically. This technique is validated when compared with the manual technique using the Bland–Altman agreement method (mean differences = −0.279 mm, upper limit = 2.2 mm, and lower limit = −2.7 mm) and Deming regression (slope = 1.06 ± 0.004). Conclusion. This study establishes a protocol to collect electrical conductivity signals in spine surgery with synchronization to the depth of the instrument. Real-time conductivity signal feedback alerts the surgeon of a probable breach in the spinal canal, so he can change the direction of the pedicle aim

Intraoperative Optical Monitoring of Spinal Cord Hemodynamics Using Multiwavelength Imaging System

The spinal cord is a major structure of the central nervous system allowing, among other things, the transmission of afferent sensory and efferent motor information. During spinal surgery, such as scoliosis correction, this structure can be damaged, resulting in major neurological damage to the patient. To date, there is no direct way to monitor the oxygenation of the spinal cord intraoperatively to reflect its vitality. This is essential information that would allow surgeons to adapt their procedure in case of ischemic suffering of the spinal cord. We report the development of a specific device to monitor the functional status of biological tissues with high resolution. The device, operating with multiple wavelengths, uses Near-InfraRed Spectroscopy (NIRS) in combination with other additional sensors, including ElectroNeuroGraphy (ENG). In this paper, we focused primarily on aspects of the PhotoPlethysmoGram (PPG), emanating from four different light sources to show in real time and record biological signals from the spinal cord in transmission and reflection modes. This multispectral system was successfully tested in in vivo experiments on the spinal cord of a pig for specific medical applications